多部分标识符“System.Data.Datarowview”无法绑定。我收到错误请帮助我 [英] The Multi-Part Identifier "System.Data.Datarowview" Could Not Be Bound. I am Getting Error Please Help Me

问题描述

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace country_state_city
{
    public partial class Form1 : Form
    {

        SqlConnection con = new SqlConnection(**************);
        
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            SqlCommand cmd = new SqlCommand("select * from Country", con);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds);
            comboBox1.DataSource = ds.Tables[0];
            comboBox1.SelectedIndex = -1;
            comboBox1.DisplayMember = "County";
            comboBox1.ValueMember = "Countryid";
            
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox1.SelectedIndex >=0)
            {
                MessageBox.Show(comboBox1.SelectedIndex.ToString());
                SqlDataAdapter da = new SqlDataAdapter("Select * From CountryState Where CountryId='" + comboBox1.SelectedValue + "'", con);
                DataSet ds = new DataSet();
                da.Fill(ds);
                
                comboBox2.DataSource = ds.Tables[0];
                comboBox2.DisplayMember = "State";
                comboBox2.ValueMember = "StateId";
            }
        }

        private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

        private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox2.SelectedIndex > 0)
            {

                SqlDataAdapter da = new SqlDataAdapter("Select * From StateCity Where StateId='" + comboBox2.SelectedValue + "'", con);
                DataSet ds = new DataSet();
                da.Fill(ds);

                comboBox3.DataSource = ds.Tables[0];
                comboBox3.DisplayMember = "City";
                comboBox3.ValueMember = "CityId";
            }
        }
    }
}

推荐答案

private void Form1_Load(object sender, EventArgs e)
{
    comboBox1.SelectedIndexChanged -= comboBox1_SelectedIndexChanged;
    SqlCommand cmd = new SqlCommand("select * from Country", con);
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataSet ds = new DataSet();
    da.Fill(ds);
    comboBox1.DataSource = ds.Tables[0];
    comboBox1.SelectedIndex = -1;
    comboBox1.DisplayMember = "County";
    comboBox1.ValueMember = "Countryid";
    comboBox1.SelectedIndexChanged += comboBox1_SelectedIndexChanged;
}

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